Safe or vault plate



Sept. 18 ,1923.-

M. l.. HARTMANN SAFE oa www' PLATE Filed April 25. 1922 Patented Sept.18, 1923.

uNlTaD STATES PATENT ouvrier..v

imma L. H AarirANN, oi' NrAeAaA rALLs, Niizw` Your, AssIeNoza 'ifo 'maclizia.- iaoauNnim eoicrANr, or NiAeAnA rms, Naw Yoax, A eoaroaA'rIoNo1l rm- SYLVANIA- sur: on. vAUL'r PLATE.

Application aledhpril 25, 1922. Serial lo. 550,484.

To all whom 'it ma/y comem'.'

Be it lmown that I, MINER L. HARTMANN, a citizen of the Niagara Falls,in the county of Niagara and State of New York, have invented a new anduseful Improvement in s afe or Vault Plates, of which the following is afull, clear, and exact descriptiontreferencerbeing had to theaccompanyin drawings, forming part of this speci cation, in

whch- Figure 1 is a plan view of a safe or vault plate made inaccordance with my mven-l tion, and l' Figure 2 is a cross section ofthe same:

The object of my invention is to provide plates for vaults or safe wallswhich are more or less impregnable to the action of high temperatureagents and llames, such as the Oxy-acetylene flame.

As safes and vaults have heretofore been constructed it is possible bymeans of the oxy-acetylene flame to cut or burn holes through the wallsor doors and gain access to the interior compartment. n

My invention consists in embedding in a matrix of cast metal more orless closel Y assembled fragments of a highly refractory material whichis not only infusible or di fieultly fusible at the temperature reachedby the Oxy-acetylene flame but is also ngt acted upon by the highlyheated and fluid iron oxide nor by oxygen. The material which I employfor the above pu se is fused ore of chromium oxide, pre erably fusedchromite. This material has a melting point which varies from about1800r C.

to about 2000 C. depending upon its purity. The material may be made inaccordance with the method set forth in my application Serial No.556,426, filed April 25, 1922, that is to say, the ore of chromium oxideis subjected to high temperature and is fused in a non-reducingenvironment. This` may be I accomplished in any ordinary form of arcfurnace with vertical electrodes de nding into the furnace pot. Theelectr. es'iiiay- United States, residing atk ber of carbon or gra hite.Graphite is preferred' on account o the lessenedamount of lace from thecarvhe furnace pot is reduction which takes bon of the electrode.preferab the furnace around the electrodes and a mass of fused chromiteforms under the action of the arc.- This material accumulates and buildsup and spreads out ina fused condition for some distance outside of thearc. The electrodes are then raised In -the therein.

In making a slab or plate for use in the construction of a bur lar proofvault I pare a dry sand mol 3 of the required shape and of a charactersuch as is used inthe making of steel castings. In this I placefragments of fused chromium ore or chroinite and then pour the moltenmetal, such as ironA orsteel into the mold in the usual manner. In aslab 10 inches thick, for instance, I would use fragments from 2 inches`to 5 inches in diameter. .The molten metal should be in a highly heatedand vry iiuid condition yso that it will ow around and penetrate all ofthe interstices of' the mass of fragments and form a strong, tough,close,` dense matrix therefor. If preferred the fragments may bepreheated so as not to chill the metal. Any metal'or alloy may 31 linedwith refractory material y such as rome brick. The ore is fed into .i

be used as a matrix. The fragments may L -ill the entire lmold andextend into every part of the slab or plateor they may be disposed inthe centerof the slab or otherwise disposed without departing from thespirit of my invention.

By the word metal in my claims, I intend to cover either `substantiallypure metals or alloys.

ferredV embodiment, the details of which The invention is not limitedto'itsvpi'e-l have been ebove set forth, but moy-be embeddedthepeinfragments of fused ore of lo otherwise embodiedv within the scope ofchromium oxide. the following claim. 8. As e new article of manufacture,e I claim: l safe or veult late formed of cast metal hnv l 1. As 'n newarticle of'menufacture, esafe ing embedd therein fragments of fused orvnufxlete formed of cast metal having chromite in e dense com t mm. ll

therein fragments of chromite. In testimony whereof have hereunto set 2.As a. new article of manufacture a'safe my hand. I

i o; mit plm formed 'of ma mm1 Living l MINER L HARTMANN.

